— allocate and free BN_CTX
A BN_CTX is a structure that holds BIGNUM temporary variables used by library functions. Since dynamic memory allocation to create BIGNUMs is rather expensive when used in conjunction with repeated subroutine calls, the BN_CTX structure is used.
allocates and initializes a BN_CTX structure.
frees the components of the BN_CTX and, if it was
BN_CTX_new(), also the structure itself.
If BN_CTX_start(3) has been used on the BN_CTX,
BN_CTX_end(3) must be called before the BN_CTX
may be freed by
c is a
NULL pointer, no action
(deprecated) initializes an existing uninitialized
BN_CTX. This should not be used for new programs. Use
BN_CTX_new() returns a pointer to the
BN_CTX. If the allocation fails, it returns
NULL and sets an error code that can be obtained by
BN_add(3), BN_CTX_start(3), BN_new(3)
BN_CTX_free() first appeared in SSLeay 0.5.1 and
have been available since OpenBSD 2.4.
BN_CTX_init() first appeared in SSLeay
0.9.1 and has been available since OpenBSD 2.6.